Lubricating oils for internal combustion engines contain in addition to at least one base lubricating oil, additives which enhance the performance of the oil. A variety of additives, such as detergents, dispersants, friction reducers, viscosity index improvers, antioxidants, corrosion inhibitors, antiwear additives, pour point depressants, seal compatibility additives and antifoam agents, are used in lubricating oils.
Current trends in the design of automotive engines require lubricating oils that have ever more enhanced performance. For example, engines are now designed to operate hotter with higher load and increased output. Such conditions put significant stress on the thermal and oxidative stability of lubricating compositions. To formulate oils that resist oxidation under such conditions and that achieve adequate operation life is both a technical and an economic challenge.
An objective of the present invention is to provide lubricating compositions that have enhanced thermal and oxidative stability.